Well then you thought wrong, 80% it is, not only in Indigo :P
Your tonemapping can also be the cause of such flat colours, together with very uniform lighting you seem to use...

Caustics are one of the major selling points of Indigo, a USP and something the Devs can be proud of. You are the first after 15 years I'm with Indigo who requests a option to disabling caustics, think about that.

An AOish look can be simulated by having pure uniform white env light and all materials set to (80%) white diffuse,
so you end up with a clay rendering.

Before thinking about adding depth to your rendering with adding such AO pass I'd rather invest some time in lighting your scene more interesting ;)

To store a scene's parameters in an indigo scene, such that it could then be used in another indigo standalone scene, like merging 2 standalone scenes, into the standalone, as 2 separate scene geometries. Or can you bring in an FBX camera, or FBX animation/mesh, and have it pan-through/play on a timeline, in an already set up scene, in the standalone itself, without using a plugin?

Or is this possible-
Set up a scene in 3ds max....save it as a scene from the Indigo plugin, and then working on another part in C4D, save that as a scene in indigo plugin, and merge the 2 in the standalone?
More like making the standalone being the 'hub'...having some components brought in from Max, some from C4d, without ever importing / exporting between the applications..

If not....please consider adding this type of FBX import paradigm...
This standalone could be so much more!

To store a scene's parameters in an indigo scene, such that it could then be used in another indigo standalone scene, like merging 2 standalone scenes, into the standalone, as 2 separate scene geometries. Or can you bring in an FBX camera, or FBX animation/mesh, and have it pan-through/play on a timeline, in an already set up scene, in the standalone itself, without using a plugin?

I would second this request: being able to 'include' other scenes through the exporters would be super helpful.

I would second this request: being able to 'include' other scenes through the exporters would be super helpful.

I hacked my version of Blendigo to include cameras like this - after tweaking in Indigo I save a separate igs with just the camera settings and then in Blender I can browse to include that external camera igs. I agree this would be great to make more official and be able to merge various things.

would be nice if you would implement hair and particles since years of asking... the earliest post asking for this very feature i saw was from 2010, is it that complicated or why do these features have such a low priority?